Polymers and copolymers of, and surgical devices made from lactide and/or glycolide and/or related compounds are well-know. See, e.g., U.S. Pat. Nos. 2,668,162, 2,683,136, 2,703,316, 2,758,987, 3,225,766, 3,268,486, 3,268,487, 3,297,033, 3,422,181, 3,442,871, 3,463,158, 3,468,853, 3,531,561, 3,565,869, 3,597,449, 3,620,218, 3,626,948, 3,636,956, 3,736,646, 3,739,773, 3,772,420, 3,733,919, 3,781,349, 3,784,585, 3,792,010, 3,797,499, 3,839,297, 3,846,382, 3,867,190, 3,987,937, 3,878,284, 3,896,802, 3,902,497, 3,937,223, 3,982,543, 4,033,938, 4,045,418, 4,057,537, 4,060,089, 4,137,921, 4,157,437, 4,243,775, 4,246,904, 4,273,920, 4,275,813, 4,279,249, 4,300,565, and 4,744,365, U.K. Pat. or Appln. Nos. 779,291, 1,332,505, 1,414,600 and 2,102,827, D. K. Gilding et al., "Biodegradable polymers for use in surgery-polyglycolic/poly (lactic acid) homo-and copolymers: 1, "Polymer, Volume 20, pages 1459-1464 (1979), and D. F. Williams (ed.) Biocompatibility Of Clinical Implant Materials, Volume II, chapter 9: "Biodegradable Polymers" (1981).
U.S. Pat. No. 4,052,988 describes random copolymers containing dioxanone and up to 50 percent by weight of other copolymerizable monomers which produce non-toxic and absorbable copolymers.
As described above, bioabsorbable surgical devices, such as surgical sutures, are known in the art. A desirable characteristic of bioabsorbable devices, such as sutures, is their ability to exhibit and maintain desired tensile properties for a predetermined time period followed by rapid absorption of the mass of the surgical device (hereinafter "mass loss").
Absorbable multifilament sutures such as Dexon, Vicryl, and Polysorb commercially available from Davis & Geck (Danbury, Connecticut), Ethicon, Inc. (Sommerville, N.J.), and United States Surgical Corporation (Norwalk, Conn.), respectively, are known in the industry as short term absorbable sutures. The classification short term absorbable sutures generally refers to surgical sutures which retain about 20 percent of their original strength at three weeks after implantation, with the suture mass being essentially absorbed in the body within about 60 to 90 days post implantation.
Long term absorbable sutures are generally known to be sutures which retain about 20 percent of their original strength at six or more weeks after implantation, with the suture mass being essentially absorbed in the body within about 180 days post implantation. For example, PDS II, a synthetic absorbable monofilament suture, commercially available from Ethicon, Inc. (Sommerville, N.J.), retains about 20 to about 30 percent of its original strength at six weeks after implantation. However, PDS II exhibits minimal mass loss until 90 days after implantation with the suture mass being essentially absorbed in the body about 180 days after implantation. Maxon, commercially available from Davis & Geck (Danbury, Conn.) is another absorbable synthetic monofilament generally fitting this absorption profile.
Therefore, it would be advantageous to provide bioabsorbable surgical devices which exhibit and maintain tensile properties for the desired period of time while having a shorter and thus improved mass loss profile, such as a long term bioabsorbable synthetic monofilament surgical suture having tensile properties and handling characteristics comparable to PDS II, which exhibits a shorter mass loss profile.
U.S. Pat. No. 4,444,927 describes a process for fabricating dioxanone articles by heating a mixture of polydioxanone and finely divided sucrose or lactose nucleating agent. The '927 patent teaches that as a result of the presence of nucleating agents, the cycling time of injection molding of the polymers can be significantly reduced in many cases. However, the '937 patent does not disclose or suggest that such blends would reduce the mass loss absorption time, let alone disclose blending fine particles of fast absorbing polymers with longer term absorbable polymers to reduce the mass loss time of the longer term absorbable polymers.